Before a TARDIS becomes fully functional, it must be primed with the biological imprint of a
Time Lord, normally done by simply having a Time Lord operate the TARDIS for the first time.
This imprint comes from the Rassilon Imprimatur, part of the biological makeup of Time Lords, which gives them both a symbiotic link
to their TARDISes and the ability to withstand the physical stresses of time travel.

tardis: I'll always be here. But this is when we talked and now even that has come to an end. There is something I did not get to say to you. doctor: Goodbye.tardis: No. I just wanted to say: Hello. Hello, Doctor. It is so very, very nice to meet you.

tardis: I'll always be here. But this is when we talked and now even that has come to an end. There is something I did not get to say to you. doctor: Goodbye.tardis: No. I just wanted to say: Hello. Hello, Doctor. It is so very, very nice to meet you.

tardis: I'll always be here. But this is when we talked and now even that has come to an end. There is something I did not get to say to you. doctor: Goodbye.tardis: No. I just wanted to say: Hello. Hello, Doctor. It is so very, very nice to meet you.